Absolute Write
http://www.absolutewrite.com/forums/
Includes a forum titled “Bewares and Background Check,” to share information about about publishers, agents, and producers. Here's where to check in about publishers, agents, and producers. Need to know if someone is legit? Want to share your experiences?

Agent Query
http://www.agentquery.com/
This is a free service which allows searches by genre. It provides agent names/contacts with the types of works each agent is seeking to represent and also lists recent book deals.